: This has been brought up a few times before if you'll search the archive and no one posted a definitive answer. I have doubts about the mnemonic/acronym explanation you were told. It's bad advice since you should lift with your legs and never your back. I think that it's probably a "backronym" where someone tries to explain an existing word as an acronym, e.g. a backronym for SPAM is Something Posing As Meat.

"Back, arms, legs, manual" may be a mnemonic for the spelling of "balm," but it isn't the origin of the word. I don't know how the reference to lifting stones might enter in. "Bomb" merely sounds similar; it has nothing to do with balm. A dictionary traces "balm," meaning a soothing ointment (hand balm, lip balm), back to a [email protected] word for balsam. For origins of words, always trust dictionaries over what someone tells you. ~rb